Passive infrared intrusion alarm systems are susceptible to false alarms caused by the detection of infrared emissions from animals or other heat sources which are not human and which do not pose a security threat. Typically, the reception of an alarm signal at a security station results in security personnel being dispatched to determine the cause of the threat. This use of security personnel to determine if an alarm indicates a real threat is expensive, especially when the monitoring station and security personnel are located at a distance from the area under surveillance.
Alternatively, the area to be monitored may be under surveillance by a more expensive video camera and occurrence of an alarm causes the security monitor to use the video camera to view the area. This technological approach, which requires special communications lines and equipment, is also expensive, especially when the area under surveillance is located a distance from the monitoring station.
The present invention provides the verification capability similar to that of a video camera but at a much reduced cost.